This invention relates to seatbelt systems for restraining and protecting an occupant in the event of an emergency situation of an automotive vehicle, and particularly to a seatbelt system for automatically fastening a restraining webbing about the occupant upon his entering the vehicle.
There have been proposed seatbelt systems in which an end portion of the occupant restraining webbing is moved by driving means to automatically fasten the webbing about the occupant upon his entering the vehicle.
In the seatbelt system of the type described, the end portion of the webbing is moved by a driving force of a motor, or the end portion of the webbing is secured to a door and the end portion is moved in accordance with the closing action of the door, so that the webbing can be automatically fastened about the occupant. Consequently, the webbing is fastened about the occupant without fail during running condition of the vechicle, thereby enabling the webbing to fully secure the safety of the occupant.
However, in this automatic fastening seatbelt system, the webbing can be moved from the webbing fastened state to the webbing released state, whereby the winding length of a retractor for winding the end portion of the webbing tends to increase. This leads to the disadvantage that, when a tensile force high in value acts on the webbing in the event of an emergency situation of the vehicle, the webbing, which has been loosely wound into a takeup shaft, is tightly wound and a length of the webbing corresponding to the portion being tightly wound is extended from the takeup shaft.